Compilare: user.cpp: In function ‘int main()’: user.cpp:144:6: warning: unused variable ‘j’ [-Wunused-variable] int j; ^ user.cpp: In function ‘void r(int&)’: user.cpp:46:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(pos==MAX)fread(f,1,MAX,stdin),pos=0; ^ user.cpp:51:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(pos==MAX)fread(f,1,MAX,stdin),pos=0; ^ user.cpp: In function ‘int main()’: user.cpp:134:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ai.in","r",stdin); ^ user.cpp:135:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ai.out","w",stdout); ^ user.cpp:136:25: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(f,1,MAX,stdin); ^